#!/usr/bin/env python
# -*- coding: utf-8 -*-

def showresult(x,Δx,n):
  print(f"x: {x:.15f}, Δx: {Δx:e}, pass: {n:2}")

y = 2.0
x = 1
n = 0

while True:
  
  Δx = (y - x * x) * 0.25
  
  if n % 2 == 0:
    showresult(x,Δx,n)
    
  n += 1
  
  ox = x
  x += Δx
  if ox == x: break
   
showresult(x,Δx,n)